Gut-associated lymphoid tissue attrition associates with response to anti-α4ß7 therapy in ulcerative colitis.

Vedolizumab (VDZ) is a first-line treatment in ulcerative colitis (UC) that targets the α4ß7- mucosal vascular addressin cell adhesion molecule 1 (MAdCAM-1) axis. To determine the mechanisms of action of VDZ, we examined five distinct cohorts of patients with UC. A decrease in naïve B and T cells in the intestines and gut-homing (ß7+) plasmablasts in circulation of VDZ-treated patients suggested that VDZ targets gut-associated lymphoid tissue (GALT). Anti-α4ß7 blockade in wild-type and photoconvertible (KikGR) mice confirmed a loss of GALT size and cellularity because of impaired cellular entry. In VDZ-treated patients with UC, treatment responders demonstrated reduced intestinal lymphoid aggregate size and follicle organization and a reduction of ß7+IgG+ plasmablasts in circulation, as well as IgG+ plasma cells and FcγR-dependent signaling in the intestine. GALT targeting represents a previously unappreciated mechanism of action of α4ß7-targeted therapies, with major implications for this therapeutic paradigm in UC.

Gut-associated lymphoid tissue attrition associates with response to anti-α4ß7 therapy in ulcerative colitis.

Targeting the α4ß7-MAdCAM-1 axis with vedolizumab (VDZ) is a front-line therapeutic paradigm in ulcerative colitis (UC). However, mechanism(s) of action (MOA) of VDZ remain relatively undefined. Here, we examined three distinct cohorts of patients with UC (n=83, n=60, and n=21), to determine the effect of VDZ on the mucosal and peripheral immune system. Transcriptomic studies with protein level validation were used to study drug MOA using conventional and transgenic murine models. We found a significant decrease in colonic and ileal naïve B and T cells and circulating gut-homing plasmablasts (ß7+) in VDZ-treated patients, pointing to gut-associated lymphoid tissue (GALT) targeting by VDZ. Murine Peyer's patches (PP) demonstrated a significant loss cellularity associated with reduction in follicular B cells, including a unique population of epithelium-associated B cells, following anti-α4ß7 antibody (mAb) administration. Photoconvertible (KikGR) mice unequivocally demonstrated impaired cellular entry into PPs in anti-α4ß7 mAb treated mice. In VDZ-treated, but not anti-tumor necrosis factor-treated UC patients, lymphoid aggregate size was significantly reduced in treatment responders compared to non-responders, with an independent validation cohort further confirming these data. GALT targeting represents a novel MOA of α4ß7-targeted therapies, with major implications for this therapeutic paradigm in UC, and for the development of new therapeutic strategies.

Ulcerative colitis is characterized by a plasmablast-skewed humoral response associated with disease activity.

B cells, which are critical for intestinal homeostasis, remain understudied in ulcerative colitis (UC). In this study, we recruited three cohorts of patients with UC (primary cohort, n = 145; validation cohort 1, n = 664; and validation cohort 2, n = 143) to comprehensively define the landscape of B cells during UC-associated intestinal inflammation. Using single-cell RNA sequencing, single-cell IgH gene sequencing and protein-level validation, we mapped the compositional, transcriptional and clonotypic landscape of mucosal and circulating B cells. We found major perturbations within the mucosal B cell compartment, including an expansion of naive B cells and IgG+ plasma cells with curtailed diversity and maturation. Furthermore, we isolated an auto-reactive plasma cell clone targeting integrin αvß6 from inflamed UC intestines. We also identified a subset of intestinal CXCL13-expressing TFH-like T peripheral helper cells that were associated with the pathogenic B cell response. Finally, across all three cohorts, we confirmed that changes in intestinal humoral immunity are reflected in circulation by the expansion of gut-homing plasmablasts that correlates with disease activity and predicts disease complications. Our data demonstrate a highly dysregulated B cell response in UC and highlight a potential role of B cells in disease pathogenesis.

Predictability in the evolution of Orthopteran cardenolide insensitivity.

The repeated evolutionary specialization of distantly related insects to cardenolide-containing host plants provides a stunning example of parallel adaptation. Hundreds of herbivorous insect species have independently evolved insensitivity to cardenolides, which are potent inhibitors of the alpha-subunit of Na+,K+-ATPase (ATPα). Previous studies investigating ATPα-mediated cardenolide insensitivity in five insect orders have revealed remarkably high levels of parallelism in the evolution of this trait, including the frequent occurrence of parallel amino acid substitutions at two sites and recurrent episodes of duplication followed by neo-functionalization. Here we add data for a sixth insect order, Orthoptera, which includes an ancient group of highly aposematic cardenolide-sequestering grasshoppers in the family Pyrgomorphidae. We find that Orthopterans exhibit largely predictable patterns of evolution of insensitivity established by sampling other insect orders. Taken together the data lend further support to the proposal that negative pleiotropic constraints are a key determinant in the evolution of cardenolide insensitivity in insects. Furthermore, analysis of our expanded taxonomic survey implicates positive selection acting on site 111 of cardenolide-sequestering species with a single-copy of ATPα, and sites 115, 118 and 122 in lineages with neo-functionalized duplicate copies, all of which are sites of frequent parallel amino acid substitution. This article is part of the theme issue 'Convergent evolution in the genomics era: new insights and directions'.

iTRAQ-based pharmacoproteomics reveals potential targets of berberine, a promising therapy for ulcerative colitis.

Previous studies by us and others have indicated that berberine is a promising therapy for ulcerative colitis (UC). However, the mechanisms of UC and the therapeutic targets of berberine are poorly understood. iTRAQ-based proteomics was utilized to characterize the proteins and pathways associated with the development of colitis and its improvement after berberine treatment. By using a modified dextran sodium sulfate (DSS) colitis as the UC model, confirmed that berberine significantly attenuated clinical symptoms and colon shorting of the colitis mice. Proteomics identified 140 and 391 proteins that were differentially expressed in the colons of DSS- or DSS plus berberine-treated mice, respectively. Subsequent verification of 15 selected differentially expressed proteins (DEPs) by multiple reaction monitoring confirmed the reliability of the iTRAQ data. Further comparisons and bioinformatics analysis demonstrated that among the identified DEPs, 26, including Hist2h2be, Tubb3, and five immunoglobulins, were oppositely regulated by DSS and DSS plus berberine treatments. In addition, five commonly dysregulated pathways, including natural killer cell-mediated cytotoxicity and RRAR signaling were identified. Network analysis revealed that proteins involved in 7 and 11 pathways in DSS and DSS plus berberine treated mice, respectively, engaged in protein-protein interactions. Our study provides the first pharmacoproteomics profiling of colitis and its recovery after berberine treatment. The proteins, pathways and networks identified provide novel insights into the pathogenesis of colitis and the action mechanism of berberine, demonstrating their values for validation in human UC which could serve as targets for the development of novel therapies for UC.

Anti-α4ß7 therapy targets lymphoid aggregates in the gastrointestinal tract of HIV-1-infected individuals.

Gut homing CD4+ T cells expressing the integrin α4ß7 are early viral targets and contribute to HIV-1 pathogenesis, likely by seeding the gastrointestinal (GI) tract with HIV. Although simianized anti-α4ß7 monoclonal antibodies have shown promise in preventing or attenuating the disease course of simian immunodeficiency virus in nonhuman primate studies, the mechanisms of drug action remain elusive. We present a cohort of individuals with mild inflammatory bowel disease and concomitant HIV-1 infection receiving anti-α4ß7 treatment. By sampling the immune inductive and effector sites of the GI tract, we have discovered that anti-α4ß7 therapy led to a significant and unexpected attenuation of lymphoid aggregates, most notably in the terminal ileum. Given that lymphoid aggregates serve as important sanctuary sites for maintaining viral reservoirs, their attrition by anti-α4ß7 therapy has important implications for HIV-1 therapeutics and eradication efforts and defines a rational basis for the use of anti-α4ß7 therapy in HIV-1 infection.

The current state of the art for biological therapies and new small molecules in inflammatory bowel disease.

The emergence of biologic therapies is arguably the greatest therapeutic advance in the care of inflammatory bowel disease (IBD) to date, allowing directed treatments targeted at highly specific molecules shown to play critical roles in disease pathogenesis, with advantages in potency and selectivity. Furthermore, a large number of new biologic and small-molecule therapies in IBD targeting a variety of pathways are at various stages of development that should soon lead to a dramatic expansion in our therapeutic armamentarium. Additionally, since the initial introduction of biologics, there have been substantial advances in our understanding as to how biologics work, the practical realities of their administration, and how to enhance their efficacy and safety in the clinical setting. In this review, we will summarize the current state of the art for biological therapies in IBD, both in terms of agents available and their optimal use, as well as preview future advances in biologics and highly targeted small molecules in the IBD field.

Efficient long-term depletion of CD20+ B cells by rituximab does not affect gut-resident plasma cells.

The vast majority of antibody-producing B cells are located within the gastrointestinal tract and are key players in maintaining homeostasis. The failure of rituximab, a potent B cell-depleting agent, to ameliorate ulcerative colitis in a single clinical trial has dampened enthusiasm to study B cells in patients with inflammatory bowel disease (IBD). However, several lines of evidence suggest that intestinal B cells may be affected in IBD. Additionally, the pathophysiological mechanisms underlying rituximab's lack of efficacy in IBD remain unclear. Here, on the basis of detailed immunophenotyping of a patient who underwent a colonoscopy 6 months after the end of rituximab-based therapy, we observed that rituximab did not deplete colon-resident plasma cells (PCs) while ablating all CD20+ B cells in tissues and in the circulation. On the basis of these observations, we propose that one factor underlying the lack of efficacy of rituximab relates to the fact that it does not affect the entire B cell compartment in tissues, sparing the intestinal-resident PCs while effectively depleting CD20+ B cell populations. Thus, we contend that, despite the results of the Rituximab study, there is a need for more intensive B cell-oriented research in inflammatory disorders, including IBD.

Augmentation in Restless Legs Syndrome: Treatment with Gradual Medication Modification.

Dopaminergic drugs can cause augmentation during the treatment of restless legs syndrome (RLS). We previously reported that sudden withdrawal of dopaminergic treatment was poorly tolerated. We now report our experience with gradual withdrawal of the dopaminergic drug during the drug substitution process using a retrospective chart review with comparison to previous data. Seven patients with RLS and dopaminergic drug-induced augmentation were treated with a gradual withdrawal of the offending drug and replacement with an alternative medication. Compared to sudden withdrawal, measured outcomes were similar but gradual tapering was better tolerated. We conclude that for augmentation in RLS, gradual tapering of the augmentation-inducing dopaminergic drug is better tolerated than sudden withdrawal. The optimal approach to treating augmentation has not been established and may differ between patients. Further study with direct comparison of strategies and a larger patient population is needed to confirm our preliminary observations.

Complementary Therapies for Parkinson's Disease: What's Promoted, Rationale, Potential Risks and Benefits.

BACKGROUND: Nearly half of all patients with Parkinson's disease (PD) utilize some form of complementary therapy often identified on the Internet and frequently not reported to their physicians. Treating physicians are sometimes unaware of such treatments, including their rationale, mechanisms, potential efficacy, and potential adverse effects. METHODS: Methods for this study included systematic Internet search of products recommended for PD, medical literature review to determine scientific rationale, any evidence of efficacy, and potential risks. RESULTS: A large number of complementary therapies are recommended for patients with PD, generally falling into the following categories: dietary and nutritional; chelation; and physical. Most have reasonable justifications based on mechanism of action and current theories on causes of neurodegeneration in PD, but few have documented evidence of benefit. Fortunately, most have few risks and side effects, although some are very expensive. The protein redistribution diet has substantial evidence of symptomatic benefit. Some antioxidative or -inflammatory supplements, aerobic exercise, Tai chi, and dance and music therapy have preliminary evidence of symptomatic benefit or potential neuroprotective effects, but more research is needed to establish efficacy. CONCLUSIONS: Patients with PD are faced with many recommendations for complementary therapies. Physicians should know about these in order to have informed discussions with their patients. Some deserve further study.

Alopecia areata universalis complicating daclizumab therapy for uveitis.

Alopecia areata (AA) is a complication of biologic therapy with several anti-tumor necrosis factor (TNF) inhibitors and efalizumab for the treatment of various autoimmune diseases. We report the case of a 51-year-old woman who developed AA universalis while undergoing treatment with daclizumab, an immunosuppressive biologic therapy, administered for treatment of inflammatory ocular disease. Although immunomodulatory agents that function by interfering with T helper cell stimulation are expected to impede autoimmune-related processes, we believe that daclizumab may be causally related to the development of AA.

Inguinal hernias, endometriosis, and other adverse outcomes in rhesus monkeys following lead exposure.

The Harlow Center for Biological Psychology (HCBP) has a cohort of rhesus monkeys that were exposed to low concentrations of lead acetate in utero or as infants. The lead-exposed animals have been followed for 19 years and have developed four cases of inguinal hernia (males), three cases of endometriosis (females), and one case of immunoblastic lymphoma (male). Retrospective analysis of the data from the original lead-exposed cohort indicates that there is a significant association between lead exposure and the development of inguinal hernia (P=.04). Endometriosis was not significantly associated with lead exposure (P=.36). A case control study also was done to determine the significance of neonatal lead exposure as a risk factor for the development of inguinal hernia and endometriosis. The risk of developing inguinal hernia was significantly increased in lead-exposed animals (OR=20.0, P=.009). The association between endometriosis and lead exposure was also strong (OR=10.13, P<.001). No unmatched variables were associated with inguinal hernia, including body weight, history of diarrhea, constipation, or intussusception. No unmatched variables were highly associated with endometriosis, including body weight, age at first parity, and history of stillbirths. However, parity and the number of stillbirths were associated with lead exposure (P=.011 and P=.041, respectively). There was an association between endometriosis and a history of hysterotomy (OR=2.09) but it was not statistically significant (P=.38). No other cases of lymphoma in unexposed animals were identified using HCBP animal health records. These data indicate that early lead-exposed rhesus monkeys may develop illnesses later in life, especially inguinal hernia and endometriosis, more frequently than unexposed monkeys. Studies of human populations with early lead exposure are warranted to determine their incidence of inguinal hernia, endometriosis, and hematologic neoplasia.